Thin Gel Research Articles

Convenient rapid prototyping microphysiological niche for mimicking liver native basement membrane: Liver sinusoid on a chip

Liver is responsible for the metabolization processes of up to 90 % of compounds and toxins in the body. Therefore liver-on-a-chip systems, as an in vitro promising cell culture platform, have great importance for fundamental science and drug development. In most of the liver-on-a-chip studies, seeding cells on both sides of a porous membrane, which represents the basement membrane, fail to resemble the native characteristics of biochemical, biophysical, and mechanical properties. In this study, polycarbonate (PC) and polyethylene terephthalate (PET) membranes were coated with gelatin to address this issue by accurately mimicking the native basement membrane present in the space of Disse. Various coating methods were used, including doctor blade, gel micro-injection, electrospinning, and spin coating. Spin coating was demonstrated to be the most effective technique owing to the ability to produce thin gel thickness with desirable surface roughness for cell interactions on both sides of the membrane. HepG2 and EA.HY926 cells were seeded on the upper and bottom sides of the gelatin-coated PET membrane and cultured on-chip for 7 days. Cell viability increased from 90 % to 95 %, while apoptotic index decreased. Albumin secretion notably rose between days 1–7 and 4–7, while GST-α secretion decreased from day 1 to day 7. In conclusion, the optimized spin coating process reported here can effectively modify the membranes to better mimic the native basement membrane niche characteristics.

Utilizing Magnetic Discs Combined with Thin Silicone Gel Sheets for Pressure Therapy in Earlobe Keloid Post-Excision

Utilizing Magnetic Discs Combined with Thin Silicone Gel Sheets for Pressure Therapy in Earlobe Keloid Post-Excision

Development of hydrogels from cell wall of Aspergillus oryzae containing chitin-glucan and wet spinning to monofilaments

Fungal mycelium is emerging as a source for sustainable bio-based materials. Fungal biomass of Aspergillus oryzae was prepared by cultivation on bread waste hydrolysate to valorize this abundant food waste. Chitin-glucan-rich alkali-insoluble material (AIM) was isolated from fungal biomass, formed into hydrogels, and wet spun into monofilaments. AIM in the form of fungal microfibers containing 0.09 g polymer of glucosamine (GlcN)/g AIM was subjected to freeze–thaw and deacetylation treatments to increase the amount of GlcN. The GlcN fraction was 0.19 and 0.34 g polymer of GlcN/g AIM, for AIM subjected to deacetylation (AIM-DAC) and freeze–thaw cycles and deacetylation (AIM-FRTH-DAC), respectively. The increased GlcN fraction enabled the formation of hydrogels via the protonation of amino groups after the addition of lactic acid. Morphological differences in the hydrogels included aggregation of the fungal microfibers in the AIM-DAC hydrogel, whereas the microfibers in the AIM-FRTH-DAC hydrogel had a porous and interconnected network. Rheological assessment revealed shear thinning behavior and gel properties of the produced hydrogels. Wet spinning of the hydrogels resulted in monofilaments with tensile strengths of up to 70 MPa and 12 % elongation at break. This demonstrates promising avenues for biomaterial development from fungal cell walls containing chitin-glucan via food waste valorization.

New phthalocyanine-hybrid glass materials for optoelectronics – Photostability and temperature-dependent optical properties

The organically modified silicate matrix (ORMOSIL) is the most commonly used solution for immobilization of the optically active organic compounds. The materials are characterized by much higher thermal and chemical resistance. The aim of the study was to obtain the hybrid material (in the form of thin films and gels) using the sol-gel method with covalently bound newly synthesized d-block metal phthalocyanine. The hybrid layers were prepared using the dip-coating technique. A series of the sol-gel syntheses based on various types of silicate matrix modifiers (trialkoxysilanes) and their molar ratios were prepared to obtain a photostable and durable material. The optical properties of phthalocyanine (fluorescence) with different concentration in the hybrid glass matrix were studied. Thermoluminescence of the hybrid materials were analyzed. Finally, tests of material stability under the exposure of UV at room temperature and additional under high-energy radiation were carried out with emission measurement in the ultraviolet range and in the temperature range 298–573K.

Confined Gel-Electromembrane Extraction of Oligonucleotides.

Gel-electromembrane extraction (G-EME) is an increasingly popular green variant of electromembrane extraction (EME). However, the electroendosmosis (EEO) flow associated with G-EME greatly limits the development of this technology. To address this challenge, the current study proposed the concept of confined G-EME (CG-EME), and a three-dimensional-printed modular device was elaborately designed to realize this concept. The device blocked the EEO flow by limiting the volume of the sample compartment. Moreover, the mesh structure at the bottom of the extraction module helps to prepare thin and stable gel films, which enhance the electromigration driving force and shorten the migration path. In addition, polar oligonucleotides, a nucleic acid analyte, were extracted for the first time to prove the concept of CG-EME. After optimization, 62% of the oligonucleotides were extracted at 50 V voltage for 15 min using a 3 mm thick agarose (3%) gel film. Finally, the application capability of CG-EME was further demonstrated by recovering DNA primers and isolating disease biomarkers (miRNA-181b) from real samples. In combination with CG-EME and quantitative polymerase chain reaction (qPCR) analysis, the upregulation of miRNA-181b expression in the peripheral blood of patients with schizophrenia was observed. In conclusion, this study proposes CG-EME to diminish EEO and push EME into the clinical field to isolate nucleic acid biomarkers, which will greatly expand the application scenarios of this emerging technology.

Analysis of Metoxyl and Galacturonate Contents from Pectin of Banana Peel Waste Combined with Sappan Wood

The production of banana plants (Musaceaea sp.) ranks first in agricultural output in Indonesia, but this is not balanced by the processing of waste from banana peels, which is a large amount. Therefore, an attempt is made to use banana peel waste as raw material for making pectin. Pectin is used as a functional component in the food industry because of its ability to form thin gels and stabilize proteins. Pectin is also used as a filler in the paper and textile industries, and as a thickener in the rubber industry. This research aims to determine the effect of extraction time and temperature on the quality of pectin from Kepok banana peels. The method used is extraction through Ultrasonic Assisted Solvent Extraction (UASE) in 40 kHz. Banana peels that had been dried and ground into powder were extracted with 0.1 N HCl at temperatures of 70 oC, 80 oC and 90 oC. The variables used in this extraction are variations in extraction time, namely 60 minutes and 80 minutes. The extracted solution is filtered and thickened to half the volume of the original filtrate by heating, then the pectin is thickened using acid ethanol. The pectin precipitate was washed using 96% alcohol until it was free of chloride and the precipitate was separated using a vacuum and then dried in an oven then to analysis of pectin using methoxyl and galacturonate as method to determine pectin quality form banana peel waste. The research results showed that the pectin quality was optimum at a temperature of 90 oC for 80 minutes with a methoxyl content of 4.12% (low methoxyl) and a galacturonic acid content of 79.96%.

'Gel-Stacks' gently confine or reversibly immobilize arrays of single DNA molecules for manipulation and study.

Large DNA molecules (>20kb) are difficult analytes prone to breakage during serial manipulations and cannot be 'rescued' as full-length amplicons. Accordingly, to present, modify and analyze arrays of large, single DNA molecules, we created an easily realizable approach offering gentle confinement conditions or immobilization via spermidine condensation for controlled delivery of reagents that support live imaging by epifluorescence microscopy termed 'Gel-Stacks.' Molecules are locally confined between two hydrogel surfaces without covalent tethering to support time-lapse imaging and multistep workflows that accommodate large DNA molecules. With a thin polyacrylamide gel layer covalently bound to a glass surface as the base and swappable, reagent-infused, agarose slabs on top, DNA molecules are stably presented for imaging during reagent delivery by passive diffusion.

Imaging a solvent‐swollen polymer gel network by open liquid transmission electron microscopy

AbstractVisualizing the network of a solvent‐swollen polymer gel remains problematic. To address this challenge, open transmission electron microscopy (TEM) was applied to thin gel films permeated by a nonvolatile ionic liquid. The targeted physical gels were prepared by cooling concentrated solutions of poly(ethylene glycol) in 1‐ethyl‐3‐methyl imidazolium ethyl sulfate [EMIM][EtSO4]. During the cooling, gelation occurred by a frustrated crystallization of the dissolved polymer, leading to a percolated, solvent‐permeated semicrystalline network in which nanoscale polymer crystals acted as crosslinks. Crystalline features ranging from ~5 to ~200 nm were observed, with the visible network strands dominantly consisting of long curvilinear crystallites of ~15–20 nm diameter. Nascent spherulites irregularly decorated the network, creating a complex structural hierarchy that complicated analyses. Lacking diffraction contrast, TEM did not visualize the many disordered, fully solvated PEG chains present in the voids between crystals. Recognizing that a network's three dimensionality is ambiguous when assessed through two‐dimensional microscopy projections, a small gel region was studied by TEM tomography, revealing a nearly isotropic three‐dimensional arrangement of the curvilinear crystallites, which displayed remarkably uniform cylindrical cross sections.

Chitosan-nanoclay embolic material for catheter-directed arterial embolization.

Minimally invasive transcatheter embolization is a common nonsurgical procedure in interventional radiology. It is used for the deliberate occlusion of blood vessels for the treatment of disease or injured vasculature, including vascular malformation and malignant/benign tumors. Here, we introduce a gel embolic agent comprising chitosan nanofibers and nanoclay with excellent catheter injectability and tunable mechanical properties for embolization. The properties of the gel were optimized by varying the ratio between each individual component and also adjusting the total solid content. The rheological studies confirm the shear thinning property and gel nature of the developed gel as well as their recoverability. Injection force was measured to record the force required to pass the embolic gel through a clinically relevant catheter, evaluating for practicality of hand-injection. Theoretical predicted injection force was calculated to reduce the development time and to enhance the physician's experience. The stability of occlusion was also tested in vitro by monitoring the pressure required to displace the gel. The engineered gels exhibited sterility, hemocompatibility and cell biocompatibility, highlighting their potential for transcatheter embolization.

Continuous flow delivery system for the perfusion of scaffold-based 3D cultures.

The paper-based culture platform developed by Whitesides readily incorporates tissue-like structures into laboratories with established workflows that rely on monolayer cultures. Cell-laden hydrogels are deposited in these porous scaffolds with micropipettes; these scaffolds support the thin gel slabs, allowing them to be evaluated individually or stacked into thick constructs. The paper-based culture platform has inspired many basic and translational studies, each exploring how readily accessible materials can generate complex structures that mimic aspects of tissues in vivo. Many of these examples have relied on static culture conditions, which result in diffusion-limited environments and cells experiencing pericellular hypoxia. Perfusion-based systems can alleviate pericellular hypoxia and other cell stresses by continually exposing the cells to fresh medium. These perfusion systems are common in microfluidic and organ-on-chip devices supporting cells as monolayer cultures or as 3D constructs. Here, we introduce a continuous flow delivery system, which uses parts readily produced with 3D printing to provide a self-contained culture platform in which cells in paper or other scaffolds are exposed to fresh (flowing) medium. We demonstrate the utility of this device with examples of cells maintained in single cell-laden scaffolds, stacks of cell-laden scaffolds, and scaffolds that contain monolayers of endothelial cells. These demonstrations highlight some possible experimental questions that can be enabled with readily accessible culture materials and a perfusion-based device that can be readily fabricated.

A model for the contraction kinetics of cytoskeletal gel slabs

Cytoskeletal gels are engineered prototypes that mimic the contractile behavior of a cell in vitro. They are composed of an active polymer matrix and a liquid solvent. Their contraction kinetics is governed by two dynamic phenomena: mechanotransduction (molecular motor activation) and solvent diffusion. In this paper, we solve the transient problem for the simple case of a thin gel slab in uniaxial contraction under two extreme conditions: motor-limited or slow motor (SM) activation regime, and diffusion-limited or fast motor (FM) activation regime. The former occurs when diffusion is much faster than mechanotransduction, while the latter occurs in the opposite case. We observe that in the SM regime, the contraction time scales as t/t0∼(λ/λ0)−3, with t0 being the nominal contraction time, and λ and λ0 being the final and initial stretches of the slab. t0 is proportional to 1/w˙, where w˙ is the average mechanical power generated by the molecular motors per unit reference (dry polymer) volume. In the FM regime, the contraction time scales as t/t1∼(1−λ/λ0)2, with t1 being the nominal contraction time, here proportional to the ratio L2/D, where L is the reference (dry polymer) thickness, and D is the diffusivity of the solvent in the gel. The transition between the SM and FM regimes is defined by a characteristic power density w˙∗, where w˙≪w˙∗ gives the SM regime and w˙≫w˙∗ gives the FM regime. Intuitively, w˙∗ is proportional to D/L2, where, at a given power density w˙, a thinner gel slab (smaller L) or including smaller solvent molecules (higher D) is more likely to be in the SM regime given that solvent diffusion will occur faster than motor activation.

Screen-Printed Impedance Sensor for Atmospheric Corrosion of Silver

The pitch of wiring on printed circuit boards has become finer for the development of small and lightweight electronic devices. There is a risk of breaking the wiring due to slight corrosion since the pitch of wring becomes finer. A sensor to monitor dew condensation and corrosion of wiring must be developed for preventing these corrosion phenomena. Our group 1,2) developed a corrosion monitoring sensor fabricated by screen printing. This sensor has a silver wiring of comb-shape on plastic sheet. Monitoring of dew condensation environment was conducted by using electrochemical impedance spectroscopy (EIS) because EIS allows information of condensation state from change of impedance. In this study, oxidation rate of silver was monitored by a screen-printed comb-shape wiring sensor. In addition, we developed a portable sheet-type counter electrode with thin gel electrolyte. Qualitative and quantitative analysis for corrosion products on silver wiring was carried out with this portable electrode after the corrosion monitoring, and Ag2S, Ag2O and AgCl were detected.References I. Shitanda, A. Okumra, M. Itagaki, K. Watanabe, Y. Asano, Sensor Actuat B-Chem, 139, 292 (2009).A. Aiba, N. Fujii, Y. Hoshi, I, Shitanda, M. Itagaki, J. Electrochem, Soc., 165, C743 (2018).

Gel Rolls Increase Percutaneous Nephrolithotomy Radiation Exposure.

Introduction: Despite increasing interest in reducing radiation doses during endoscopic stone surgery, there is conflicting evidence as to whether percutaneous nephrolithotomy (PCNL) positioning (prone or supine) impacts radiation. We observed clinically that a patient placed prone on gel rolls had higher than expected radiation with intraoperative CT imaging and that gel rolls were visible on the coaxial imaging. We hypothesized that gel rolls directly increase radiation doses. Methods: Anthropomorphic experiments to simulate PCNL positions were performed using a robotic multiplanar fluoroscopy system (Artis Zeego Care+Clear, Siemens) and a 5-second coaxial imaging protocol (5s BODY). A fluoroscopy phantom was placed in various positions, including prone on a gel roll; prone on blankets of equal thickness; prone and supine directly on the table; and modified supine (MS) positions using a thin gel roll or rolled blanket. Impacts of C-arm direction and use of a 1 L saline bag were also evaluated. Measured dose area product (DAP) was compared for the groups. Results: Measured DAP was found to increase by 146 μGy*m2 (287%) when prone on gel rolls compared with only 62.29 (23%) when placed on blankets of equal thickness, although the model likely both overstates the relative impact and understates the absolute impact that would be seen clinically. Measured DAP between experimental groups also varied considerably despite fluoroscopy time being held constant. Conclusions: Our experiments support our hypothesis that gel rolls directly increase radiation dose, which has not been previously reported, using an anthropomorphic model. Surgeons should consider radiolucent materials for positioning to limit radiation exposure to patients and the surgical team.

High-Sensitivity and Fast-Response Humidity Sensor Based on a Simple Fiber-Tip Interferometer With Thin Agarose Gel Coating

High-Sensitivity and Fast-Response Humidity Sensor Based on a Simple Fiber-Tip Interferometer With Thin Agarose Gel Coating

Induction and Stabilization of Columnar Mesophases in Fluorinated Polycyclic Aromatic Hydrocarbons by Arene-Perfluoroarene Interactions.

The straightforward synthesis of several Fluorinated Polycyclic Aromatic Hydrocarbons by the efficient, transition-metal-free, arene fluorine nucleophilic substitution reaction is described, and the full investigation of their liquid crystalline and optical properties reported. The key precursors for this study, i. e. 2,2'-dilithio-4,4',5,5'-tetraalkoxy-1,1'-biphenyl derivatives, were obtained in two steps from the highly selective Scholl oxidative homo-coupling of 3,4-dialkoxy-1-bromobenzene, followed by quantitative double-lithiation. In situ room temperature nucleophilic annulation with either perfluorobenzene or perfluoronaphthalene leads to 1,2,3,4-tetrafluoro-6,7,10,11-tetraalkxoytriphenylenes and 9,10,11,12,13,14-hexafluoro-2,3,6,7-tetraalkoxybenzo[f]tetraphenes, respectively, in good yields. Exploiting the same strategy, subsequent double annulations resulted in the formation of 9,18-difluoro-2,3,6,7,11,12,15,16-octa(alkoxy)tribenzo[f,k,m]tetraphenes and 9,10,19,20-tetrafluoro-2,3,6,7,12,13,16,17-octakis(hexyloxy)tetrabenzo[a,c,j,l]tetracenes, respectively. Despite the presence of only four alkoxy chains, the polar "Janus" mesogens display a columnar hexagonal mesophase over broad temperature ranges, with higher mesophase stability than the archetypical 2,3,6,7,10,11-hexa(alkoxy)triphenylenes and their hydrogenated counterparts. The improvement or induction of mesomorphism is attributed to efficient antiparallel face-to-face π-stacking driven by the establishment of non-covalent perfluoroarene-arene intermolecular interactions. The larger lipophilic discotic π-extended compounds also exhibit columnar mesomorphism, over similar temperature ranges and stability than their hydrogenated homologs. Finally, these fluorinated molecules form stringy gels in various solvents, and show interesting solvatochromic emission properties in solution as well as strong emission in thin films and gels.

An extremely safe and flexible zinc-ion hybrid supercapacitor based on a scalable, thin and high-performance hierarchical structured gel electrolyte

High performance and low cost energy storage electronic equipments, together with flexibility and safety, is a major progress in portable and wearable electronics. Unfortunately, flexible batteries are greatly limited due to their inherent cost and safety drawbacks. Herein, we build an extremely safe and flexible quasi-solid-state zinc-ion hybrid supercapacitor (ZHSC) by a scalable, thin, and high-performance hierarchical gel electrolyte including the electrospun polyacrylonitrile (PAN) matrix, polyacrylamide (PAM) and zinc salt. Benefiting from the unique interface and superior electrochemical performance of the well-designed electrolyte, the flexible ZHSC achieves a high energy density and power density (132.5 Wh kg−1 and 1244.4 W kg−1, respectively), high specific capacity (106.0 mAh/g at 1.0 A/g) and prominent cycling stability (100% capacity retention after 15 000 cycles at 10.0 A/g). More importantly, the quasi-solid-state ZHSC exhibits an extreme safety and a high wearability outperforming traditional flexible batteries and can continuously work in various extreme conditions, such as hammering, burning, washing, cutting, bending and piercing. It is believed that this hierarchical structured gel electrolyte provides a new platform and pave the way for flexible and wearable electronics with high performance and safety.

Glucose Response Kinetics and Permeability of a Composite Hydrogel Membrane

A series of composite hydrogel films containing 3-aminophenylboronic acid (AAPBA) with different thicknesses based on chitosan (CS) interpenetrating microgels were prepared on glass sheets. The gel film’s response to glucose was measured by ultraviolet spectrophotometry. The results showed that the gel with 10 mol% AAPBA showed the strongest optical response. Alizarin red S (ARS) and methyl orange (MO) were both adsorbed and desorbed from the gel film. The pore diffusion coefficient of the non-interacting solute, methyl orange, showed that the hydrogel had good permeability to water-soluble organic molecules. The apparent diffusion coefficient (8.05 × 10−8 cm2/s) of the thin gel (0.157 mm) was lower due to the influence of the kinetics of the gluconophile bond of 3-aminobenzoborate semisulfate (PBA) or due to a structural rearrangement. The diffusion coefficient of the thicker gel (0.430 mm) was 1.1 × 10−7 cm2/s, and glucose diffusion was the rate-limiting process. The specific amount of ARS bound in the gel was 27 μmol/mL, which was consistent with the amount of PBA fixed in the gel (25 μmol/mL). MO underwent nonspecific binding in the gel. The photoresponse of the gel toward glucose was reversible under physiological pH. The linear response and stability of the gels toward glucose suggest they may be used in various glucose-sensing technologies.

Cleaning testing of nineteenth-century plaster surface models with thin polyacrylamide-based gel layers attached to flexible polyethylene films

This paper explores the cleaning efficacy of polyethylene-supported 15-min photo-crosslinked poly (acrylamide-co-benzophenone) surface-attached gels (SAGs) on gypsum plaster surface models inspired by nineteenth-century casts. Cleaning tests were performed on plaster surface models with and without organic and inorganic coatings, which had been exposed to accelerated ageing by heat, humidity, and light after artificial soiling. The specific types of SAG systems were selected based on their water loading and dehydration capacities. The SAGs were loaded with customized solutions and applied on the plaster models for one minute. Cleaning efficacy was evaluated with visible reflectance, UV fluorescence photography, scanning electron microscopy, colorimetry, UV/Vis spectrophotometry, glossimetry, high resolution 3D microscopy, attenuated total reflection Fourier transform infrared spectroscopy and 2D Fourier transform infrared imaging. The SAGs provided fast and minimal wetting of the substrates, prevented excessive liquid spreading and allowed the effective liquid contact with the soiled gypsum plaster surface. A striking removal of soils from the gypsum plaster surface models was observed, which suggests convenient application of the SAG systems for the cleaning of historical plaster objects.

A supramolecular gel with unique rheological properties for treating corneal virus infection

Herpes simplex keratitis (HSK) caused by herpes simplex virus-1 infection of the cornea has taken a significant toll on the visual health of people worldwide. Anti-viral hydrogels are preferred in the treatment of HSK due to enhanced topical drug retention and reduced side effects, however, current polymer-based gelling systems usually generate clumpy or uneven gel layers on ocular surface, and are easily cleared by eyelid blinking. This study proposes a supramolecular gel co-assembled by all-small-molecule building blocks including ganciclovir and 2′-deoxyguanosine in the presence of potassium ions. The developed gel performs fascinating rheological and texture properties including high viscoelastic, good spread ability, and deformation recovery behavior, enabling the formation of a uniform and thin gel layer on ocular surface to resist the clearance by eyelid blinking and tear washing. The gel shows similar ocular convenience, but much longer drug retention in ocular tissues and higher therapeutic efficacy compared to the clinical ganciclovir gel on the primary and recurrent mouse HSK models, rabbit HSK models, and also efficiently inhibited the HSV-1 replication in ex vivo human corneal tissues. The results suggest that this all-small-molecule supramolecular gel could be a promising drug formulation for treating HSK. Data and materials availabilityThe main data supporting the results in this study are available within the paper and its Supplementary Information. The associated raw data and analyzed datasets are too large to be readily shared publicly, but they are available from the corresponding author on reasonable request.

MP35-17 GEL ROLLS SUBSTANTIALLY INCREASE RADIATION DOSE IN PRONE PERCUTANEOUS NEPHROLITHOTOMY (PCNL)

You have accessJournal of UrologyCME1 Apr 2023MP35-17 GEL ROLLS SUBSTANTIALLY INCREASE RADIATION DOSE IN PRONE PERCUTANEOUS NEPHROLITHOTOMY (PCNL) Kayvon Kiani, Eric Ballon-Landa, Xavier Glover, Brett Wiesen, and Mark Sawyer Kayvon KianiKayvon Kiani More articles by this author , Eric Ballon-LandaEric Ballon-Landa More articles by this author , Xavier GloverXavier Glover More articles by this author , Brett WiesenBrett Wiesen More articles by this author , and Mark SawyerMark Sawyer More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003269.17AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Prone percutaneous nephrolithotomy (PCNL) has been associated with higher fluoroscopy doses than supine PCNL. As part of a QI project, the authors now routinely use an Artis Zeego Care+Clear™ (Siemens) floor-mounted robotic multiplanar fluoroscopy system (RMPFS) to perform ultra-low-dose (ULD) intraoperative CT scans (ICT) during treatment of large stones. Despite lower BMI (27.6 vs. 30.0) and the same protocol (5s BODY CARE), the ULD ICT dose area product (DAP) for the single prone PCNL case was 84% higher (1036 vs. 564 uGy*m2) than when performed supine (n=26). Because gel rolls were visible in coaxial imaging, we hypothesized that gel rolls directly increased radiation exposure. METHODS: Ex vivo experiments were performed with RMPFS 5 s BODY protocol coaxial imaging using a prone-positioned fluoroscopy phantom placed on a gel roll; placed on blankets of equal thickness; or directly on the table. Spins were also performed in the supine and modified supine positions; using a thin gel roll or rolled blanket. Reported DAP was compared for the groups. RESULTS: Mean DAP was 3.9 times higher when the phantom was prone on gel rolls than directly on the table; and 3.2 times higher than prone on blankets. Thus, total radiation dose increased by 287% when gel rolls were used for positioning. With blankets, the total radiation dose was 23% higher in the prone position. There was a modest 5.6% increase in DAP between prone and supine positioning. In the modified supine position the use of a thin gel roll increased the total radiation dose 3–8% compared to blankets. CONCLUSIONS: Our hypothesis was confirmed experimentally with a standardized protocol that gel rolls directly increase measured radiation dose. Surgeons should consider radiolucent materials for positioning to limit radiation exposure to patients and the surgical team. Following this observation, the authors have substituted rolled blankets for gel rolls for PCNL positioning. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e476 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Kayvon Kiani More articles by this author Eric Ballon-Landa More articles by this author Xavier Glover More articles by this author Brett Wiesen More articles by this author Mark Sawyer More articles by this author Expand All Advertisement PDF downloadLoading ...